ollypenrice

Great. I think the second one brings the nebula forwards a little and looks crisper. I must say that I do like it. How about playing with Ha/OIII/OIII to get close to a natural colour rendition? Olly

Hi Rodd, I can't see any difference in resolution between bin 1 and bin 2 and the bin 2 will take more sharpening. It looks very crisp either way. Nice. Olly

This has to be an interesting project. I think that the question is, how best to present it. My initial thought is that an animated GIFF, flipping between one and the other, with a clear explanation of where the difference came from, would be the most effective format I can think of. (Not that I have the slightest competence in this issue.) The new information certainly changes our perception of this familiar target. Olly

I have both CC and CS3. For astrophotography there is nothing I miss when in CS3 (where I sometimes work because I haven't found the mental energy to transfer all my actions!) This despite my sometimes quite elaborate processing. I would just dust off your old CS3. In fact I prefer the multiple images screen in CS3, come to think of it. And the shortcut to 'feather selection,' which I'm always using, is 2 fingers instead of 3. Olly

Let's start a new thread... Olly

Yes, it's a big improvement for me, too, and I like Maurice's analysis of true red versus saturated brown. I can see our RASA exposure times going up! At least, that way, we'll have some hope of keeping up with the incoming data... lly

The rule of thumb is that your tracking accuracy in arcseconds needs to be no more than half your image scale in arcseconds per pixel. Without guiding, this is going to be hard to achieve. As far as other things go, around 2 arcsecs per pixel is nice in that each pixel gets enough light, you only need a tracking accuracy of an arcsecond and you'll be getting close to what the seeing will allow in terms of resolution. But you can make good images at far coarser pixel scales. These are at 3.5"PP. https://www.astrobin.com/full/383965/0/ https://www.astrobin.com/full/301531/0/ In your case a star removal software would be a big help, either Starnet++ or StarXterminator. (I prefer the latter.) They allow you to remove the stars and then replace them with the same ones given a much gentler stretch. Any miss-shapes will be far less obtrusive. Olly

Another Photoshop trick, which might be available in GIMP, is to go into Image-Adjustments-Selective Colour and lower the cyans in red. This boosts signal from Ha in the red channel. Olly

Do you suspect the presence of some ionized hydrogen mixed in with the dust? I suppose the test would be an Ha-only capture of the same region. Olly

You can't shorten the train behind the scope. The camera chip needs to lie on the focal plane, which is a fixed distance behind the objective. What you can do is use a rigid extender which requires less of the drawtube to be extended. There has been a fad among some manufacturers to make shorter main tubes with longer longer drawtubes which sometimes leaves the drawtube under-supported when well extended. Olly

I would see what you can get out of this setup. What I would not do is throw any money at it. When it comes to spending, I would spend on a better-adapted OTA. Small pixels remove the need for, or advantage of, long focal lengths. Olly

I wouldn't concentrate too much on payload weight. Of far greater importance is the relationship between tracking accuracy and pixel scale. The finer your pixel scale, the better your tracking accuracy needs to be. Olly

I don't think any of us has ever taken an M31 with which we remain satisfied for long! There are so many decisions to make about about dynamic range, colour and local contrasts. I understand your desire for a 'fuller body,' though everything is in place here, which is good going for starters. I think several things would help. 1) A higher black point would make the contrast with the galaxy less stark. That really is a jet black sky and very glossy-smooth. It does looked clipped to my eye though the faint stuff just above it in brightness is there. (The clipped look reduces apparent depth, the argument goes, because it creates a sense of a reflective picture surface which bounces the view back out at the observer rather than drawing them in. I think I buy this idea which I first heard from Dennis Isaacs. 2) It seems colour-cold, to me, meaning a thinner overall look. Warmer colours have more body. The reds are a little acid yellow and the blues a little cyan. A tip towards magenta would, I think, bring more body. 3) Smaller, softer stars would let the galaxy step forward. By the way, Paul and I did a test run on M31 in the RASA 8 and were knocked out by the result so we're carrying on. I found StarXterminator worked perfectly on the fully stretched image, meaning we could put the stars back at any size we liked.) Small stars bring the gallaxy forward and make it look 'bigger' due to relative scale. Olly

That's a great success. The mosaic is seamless and balanced. Olly

Yes, the only issue with a Petzval design is, 'Can I get the chip onto the focal plane of the telescope with the hardware I have?' If the drawtube is too long or too short for your camera's chip distance (the distance between its front attachment point and its chip) you won't be able to. But it seems that you can, so all is good. However, mounting hardware can introduce tilt so the less of it you have the better - and it should all be screw fit. As for chip tilt in the camera, there's a thread on how to tackle this. Olly

The extra depth coming from your longer integration has given more nuances to the dusty features. The sheer volume of 'information' in this image is astonishing. It's tremendous. For my taste the colour is slightly over-pushed, notably in the reds. (Not so much in the Ha streak as in the dusty features. I think a little less might be a lot more in this case.) Olly

To push the colour harder you need a good signal to noise ratio in the image. Because this image is already showing some graininess I doubt it would stand much intensification of the colour. Olly

Yes, we now have no trouble photographing what is really little more than glorified background sky. By the way, your recent image showing parts of ours above in more detail is stunning. Olly

I wonder about this as well. Perhaps the dark (void?) patches are created as stellar winds or shock fronts collect and compress the gas into tight clumps which we see as the dusty nebulae. The region within the arcs of the Veil is notably transparent with a high star count because that volume has been swept clear by the expanding shock front. Yes, the sea creatures do seem to be fleeing radially from a point on the right. However, the real movement has to be in the opposite direction since the 'head' ends of the fish are surely being swept by winds flowing left to right. All very curious. Olly

Using our existing images of the Shark and the Angler Fish, Paul Kummer shot the panels needed to make this widefiled mosaic (15 in all.) He also did the pre-processing and mosaic combination in APP. The post processing is mine, here. I have to say 'Hats off' to Paul because the linear mosaic was flawlesss, the best I've ever worked with. Even the Equalize adjustment in Photoshop revealed no anomalies whatever. For the first time since I've had it, StarXterminator wasn't effective so I had to include the stars in the stretches. One early stretch was done through a layer mask made of an equalized copy. There is no noise reduction in this rendition. The streak of supernova remnant at the bottom of the image hardly showed in a standard stretch but the signal was there. Likewise the OIII and Ha for the small planetary. This is purely an OSC image with no narrowband filtration so the problem was simply one of isolating the NB signal contained in the colour. I was amazed by how strong the Ha turned out to be because I know this SNR from a run in Ha some years ago. I didn't use it here because its FOV wasn't wide enough. RASA 8/ASI2600 OSC/Avalon linear. Remote for Paul, a few metres away for me. Olly

Sweetly done. Bravo. Olly

I love this object. We did it here with a FOV too small to include the cluster but it really is something different. Nicely done, as usual. Olly

I host several Mesus and have hosted several 10 Microns. In terms of 'just working,' Mesu are way ahead. Simple as that. No grilled circuit boards, no returns for backlash adjustment, no returns for refund... My sample is still small and, therefore, anecdotal, but there it is. Olly

Certainly the first generation Mesus have no way of disengaging the drive so balance is hit and miss in the sense that you just do your best to guess when it feels about equal both ways to the push of your fingers. I've never had any issues with my guesses being outside the mount's ability to cope, though. Thinking aloud, maybe a heavier payload will be more demanding but will also be easier to judge? Olly

Those are great. The de-starring routines work really well with NB and I like your fully starless one. In broadband I'm not so sure, partly because I can't get them to work as well as you have and partly, perhaps, because broadband seeks to be 'natural.' Either way, once you have a perfectly de-starred image you have absolute control over the starfield, which is an incredible step forward in astro-image processing. Olly